1. Field of the Invention
The present invention relates to a liquid crystal display device, and particularly, to a liquid crystal display device which is capable of improving a phenomenon that a user wearing (polarized) sunglasses cannot view images when using, for example, a vehicle-loaded display or a mobile phone.
2. Discussion of the Related Art
In general, a liquid crystal display (LCD) device is driven using an optical anisotropy of a liquid crystal and a polarizing characteristic thereof. Here, since the liquid crystal is configured to be long and thin, molecules thereof are arranged with a direction. And, the direction of the modules can be controlled by additionally applying an electric field to the liquid crystal.
Thus, if the arrangement of the molecules of the liquid crystal is changed by additionally adjusting a size of the electric field applied to the liquid crystal, a polarizing characteristic of an incident light having passed through a liquid crystal layer is changed. And accordingly, the amount of light passing through a polarizer is adjusted thus to express image information.
Currently, an Active Matrix LCD (AM-LCD) in which Thin Film Transistors (TFTs) and pixel electrodes connected thereto are arranged in a matrix form is mostly focused on because it has excellent resolution and capability for implementing a moving picture.
FIG. 1 is an exploded perspective view showing a related art LCD device.
As shown in FIG. 1, an LCD device 60 includes a backlight device 50 for generating light and a display device 40 disposed at an upper side of the backlight device 50 so as to displaying images by receiving light from the backlight device 50.
The backlight device 50 includes a lamp device 51 including a lamp 51a generating light and a lamp housing 51b for protecting the lamp 51 a from an external impact, a light guide plate 52 for guiding the light from the lamp device 51 to a liquid crystal panel 10, a reflection plate 54 for reflecting light upwardly by being disposed at a lower side of the light guide plate 52, and an optical sheet 53 composed of a diffusion sheet 53a for changing a characteristic of the light having passed through the light guide plate, a prism sheet 53b and a protection sheet 53c. 
The display device 40 includes the liquid crystal panel 10 and upper and lower polarizers 20, 30 respectively provided above and below the liquid crystal panel 10. The liquid crystal panel 10 includes a TFT substrate 11 on which electrodes are formed, a color filter substrate 12 and a liquid crystal layer interposed between the upper and lower polarizers 20, 30. Here, the upper and lower polarizers 20, 30 are provided with an adhesive layer 21 for adhering to the liquid crystal panel 10.
The polarizers 20, 30 are attached onto upper and lower surfaces of the liquid crystal panel 10, accordingly light emitted from the backlight device 50 is made to be incident on the liquid crystal panel 10 through the linear polarizer 20.
LCD devices, such those in a vehicle-loaded display or a mobile phone, are frequently exposed to external environment. Here, a person may watch a screen while wearing polarized sunglasses. In the case of polarized sunglasses, light reflected from sunlight is made to be incident into eyes of users in a horizontal direction. The polarized sunglasses reduce the horizontal light, thereby reducing eye fatigue.
However, in case of the vehicle-loaded display such as a navigation or the mobile phone, for example, an angle not allowing an image to be viewed exists according to an angle between the upper polarizer of the liquid crystal panel and an absorption axis of the polarized sunglasses. Accordingly the image cannot be viewed at this angle. In this case, the user may repeatedly put on and take off the polarized sunglasses, which causes the user to feel annoyed.